Atmospheric injections of nuclear debris: Strontium 89 and 90 from Chinese weapons tests

Abstract

The concentrations of 89 Sr and 90 Sr in a total of 455 samples of individual rain and snow collected at Fayetteville (36°N, 94°W), Arkansas, were determined radiochemically during the period between April 1973 and June 1981. Nine atmospheric nuclear tests were conducted by the government of China at Lop Nor (40°N, 90°W) during the period 1973–1981. The Chinese nuclear tests of June 27, 1973 (3‐megaton, the 15th test); June 17, 1974 (1–2 megaton, the 16th); January 23, 1976 (reported to have been a low‐yield device, the 18th); and November 17, 1976 (4‐megaton, the 21st) injected the bulk of the nuclear debris into the stratosphere. The values of mean residence times ranging from 7 to 20 days obtained after the 19th, 22nd, 23rd, and 24th Chinese tests were similar to those reported earlier for the mean residence time of nuclear debris injected into the troposhere. The cycling effect of the nuclear debris was observed after the 22nd Chinese test of September 17, 1977, and the 25th Chinese test of October 16, 1980.